Lab Experience with audio 2021
Cardiorespiratory Fitness Lab Experience
Chapter 15
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Cardiorespiratory Fitness
The ability to perform large muscle, whole body physical activity of moderate to high intensity for relatively long periods of time.
The ability of the circulatory and respiratory systems to adjust to vigorous exercise and recover from the effect of such exercise.
It is important to measure cardiorespiratory fitness because it is an important indication of your overall health and a leading predictor of your life expectancy.
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Graded Exercise Tests
Cardiorespiratory fitness measured using:
Treadmill
Cycle ergometer
Stepping bench
Incremental tests
Work rate increases every 2–3 minutes
until predetermined endpoint is reached
Tests can be maximal or submaximal
Graded Exercise Tests: Measurements
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Graded Exercise Tests: Measurements
Heart Rate
Measured by
Palpation
Carotid or radial artery
Stethoscope
On chest wall
ECG
Heart rate displayed on monitor
Measured during exercise or in recovery
Recovery HR should be measured within first 15 seconds
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Ratings of Perceived Exertion (RPE)
Feelings of effort, strain, discomfort and fatigue a person feels during exercise.
Used to regulate and measure intensity of physical activity.
3 different scales can be used:
Borg (0 – 10)
Borg (6 – 20)
OMNI (0 – 10)
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Borg Scale (0 – 10)
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Borg (6 – 20) Scale
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OMNI Cycle Scale
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VO2 max
Maximum oxygen consumption (VO2 max)
the greatest rate at which oxygen can be taken in and utilized during exercise
The gold standard measure of cardiorespiratory fitness
Depends on work instrument
Highest values typically measured on treadmill
Walking ~6% lower than running
Lower values (~5–11%) on cycle ergometer
VO2 Max
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Metabolic Responses to Exercise: Influence of Duration and Intensity
Oxygen Uptake during Incremental Exercise
Oxygen uptake increases linearly until maximal oxygen uptake (VO2 max) is reached
No further increase in VO2 with increasing work rate
VO2 max
“Physiological ceiling” for delivery of O2 to muscle
Affected by genetics and training
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Oxygen Uptake during Incremental Exercise
Physiological factors influencing VO2 max
Maximum ability of cardiorespiratory system to deliver oxygen to the muscle
Ability of muscles to use oxygen and produce energy aerobically
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Changes in Oxygen Uptake During Incremental Exercise
Metabolic Responses to Exercise: Influence of Duration and Intensity
Figure 4.7
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Measurement of VO2 max
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Measurement of VO2 max
Watch the V0 2 Max Test Video
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Estimation of VO2 max From Last Work Rate
Direct measurement of VO2 max is often not practical (complexity and cost)
Can use equations to calculate estimated VO2 max from the last stage of GXT
Must allow time for subject to reach steady state in each stage
VO2 Max
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Estimation of VO2 max From Submaximal Heart Rate Response
Measure HR at several submaximal work rate
Up to 70–85% age-predicted maximal HR (220 –age)
Extrapolate submaximal HR to estimate VO2 max
A line is drawn through the HR points measured during the test and extrapolated to the age-adjusted estimate of maximal HR
Another line is dropped down from that point to the x-axis, and the VO2 max is identified
VO2 Max
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Estimation of VO2 max from Submaximal Treadmill Test
Graded Exercise Test: Protocols
Figure 15.5
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Estimation of VO2 max From Submaximal Heart Rate Response
Problems
SD of Age-predicted maximal HR is ±11 beats•min–1
Can result in over- or underestimation of VO2 max
Other factors affect submaximal HR response
e.g., dehydration, temperature, medications
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Metabolic Equivalents (MET)
Expression of the rate of energy expenditure at rest
1 MET = energy cost at rest
1 MET = 3.5 ml•kg–1•min–1
Example:
Submax test estimated a VO2max of 11.6 METS
Convert METS to ml•kg–1•min–1 by multiplying by 3.5
11.6 x 3.5 = 40.6 ml•kg–1•min–1
Metabolic Equivalents
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Aerobic Fitness Classifications
Tests for Estimating CRF
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